1. Bring a large pot of salted water to a goil. Meanwhile, heat oil in a large saucepan over medium heat. Cook shallot, stirring occasionally, until softened, 3 to 5 minutes. Stir in chile flakes and 3/4 tsp salt; whisk iin prosecco and creme fraiche. Bring to a boil over medium high heat and reduce to 1 3/4 cups, 10 to 15 minutes.